An important concern in the field of gas turbine engines is the retention of blades on the periphery of rotatable turbine discs. Typically, those blades are held radially and circumferentially on the periphery of those discs by means of a dovetail joint. For example, the root, or radially innermost end, of each turbine blade may have a dovetail projection inserted axially into a complementary slot in the periphery of the disc. The blades may be conventionally retained axially in their respective slots by annular cooling plates fastened to one or both sides of the disc with nuts and bolts. Those nuts and bolts, however, may increase windage and fluid temperature in the engine, especially when they are used to secure together rotatable components in the gas turbine engine. Also, stress concentrations may develop at the bolt holes and must be suitably accommodated. Yet further, a large number of nuts and bolts are usually required, thus complicating assembly and disassembly of the cooling plate to the disc.
To avoid the problems attending the retention of turbine blades on the periphery of the turbine discs with cooling plates bolted to the turbine disc, boltless retainers have been developed.
For example, U.S. Pat. No. 4,304,523 - Corsmeier et al, assigned to the present assignee, discloses a boltless blade retainer secured in a recess in a turbine disc by a split retainer ring. Assembly of the blade retainer and retainer ring to the turbine disc requires compression and clamping tools.
U.S. Pat. No. 4,171,930 - Brisken et al, assigned to the present assignee, discloses a U-shaped retainer ring for axially holding a boltless blade retainer to a turbine disc.
The boltless retainers described in the patents referred to above have been satisfactory for their intended purposes. Applicant has developed, however, a boltless retainer ring which is easier to assemble, resists permanent mechanical deformation, provides clamping force comparable to that provided by nuts and bolts, and does not require manufacturing tolerances as tight as those required for prior boltless retainers.
It thus is an object of the invention to provide new retaining means effective for providing clamping forces without the use of nuts and bolts.
It is another object of the invention to provide a novel retainer ring which requires no special tooling to assemble it to mechanical components to be secured together.
It is another object of this invention to provide a novel retainer ring which resists permanent mechanical deformation.
It is yet another object of this invention to provide a novel retainer ring for clamping together at least two members without the need for tight tolerances in the manufacture of the ring.